The bottom is 10, 10 - 3 - 3 (the sides on top) = 4 so we know the middle part is 4.
We know that both of the "small ups" are 2 and the "longer ups" are 5.
Adding this altogether we get:
3 + 3 + 2 + 2 + 4 + 10 + 5 + 5 =
6 + 4 + 4 + 10 + 10 =
10 + 4 + 20 =
14 + 20 =
= 34
So our answer is B. 34 cm
Hope this helps, have a nice day! :D
(I answered in the comments, but one was deleted so I am answering this here too!)